What Is Bookkeeping and What Does a Bookkeeper Do?

What Is Bookkeeping?

Bookkeeping is the day-to-day recording and organising of a business's financial transactions. Every sale, purchase, payment and receipt is logged, categorised and matched to the bank account, creating an accurate, up-to-date record that tax returns, VAT filings and year-end accounts are all built on.

That is the short answer. The longer answer is that bookkeeping is the raw material of everything financial in your business. Your VAT return, your Self Assessment, your statutory accounts, your balance sheet and your cash flow statement all start life as bookkeeping entries. Get the bookkeeping wrong and everything built on top of it is wrong too, including your tax bill.

It is also a legal requirement. HMRC and Companies House both expect you to keep accurate financial records, and there are penalties if you cannot produce them. We cover exactly what you must keep, and for how long, later in this guide.

This article explains what a bookkeeper actually does, the difference between single-entry and double-entry bookkeeping, how a bookkeeper differs from an accountant, the records HMRC requires, what Making Tax Digital means for you, and what bookkeeping costs in the UK.

What Does a Bookkeeper Actually Do?

"Keeping the books" sounds vague, so here is what the work looks like in practice. A bookkeeper working for a typical small business will handle most or all of the following.

Recording transactions. Every sale, purchase, expense and payment is entered into the accounting software and coded to the right category. Modern bank feeds pull transactions in automatically, but a human still needs to check and categorise them correctly.
Bank reconciliation. Matching every entry in the books against the actual bank statement. This is the single most important check in bookkeeping, because it proves the records reflect reality. When the books and the bank agree, you can trust the numbers.
Sales invoicing. Raising invoices, applying the correct VAT treatment, and recording payments as they arrive.
Credit control. Chasing overdue invoices and keeping an eye on who owes the business money (accounts receivable) and who the business owes (accounts payable). Slow-paying customers kill more small businesses than weak sales do, so this matters more than it sounds.
VAT returns. Preparing the figures for each quarter's VAT return and submitting it through Making Tax Digital compatible software. If you want to sense-check a figure, our free VAT calculator adds or removes VAT at the standard and reduced rates.
Payroll data. Recording wages, PAYE, National Insurance and pension contributions so the payroll figures in the accounts match what was actually paid and reported to HMRC.
Expense and receipt management. Capturing receipts (these days usually by photographing them into the software) and attaching them to the matching transactions, so the evidence HMRC might ask for is there.
Producing basic reports. A good bookkeeper keeps the records clean enough that you can pull a profit and loss report or an aged debtors list at any time and trust what it says.

A useful way to think about it: the bookkeeper keeps the financial record of the business accurate in real time. Everyone else, including your accountant and HMRC, then works from that record.

Single-Entry vs Double-Entry Bookkeeping

There are two basic methods of keeping books, and the difference matters more than most guides let on.

Single-entry bookkeeping records each transaction once, like a personal cash diary. Money in, money out, running total. It is simple, and it can work for a very small sole trader with few transactions and no stock, equipment or borrowing. Its weakness is that it only tracks cash movements. It does not track what you own (assets) or what you owe (liabilities), and because nothing has to balance, errors can sit undetected for months.

Double-entry bookkeeping records every transaction twice, once as a debit and once as a credit, in two different accounts. The two sides must always be equal, so the books are self-checking: if total debits and total credits do not match, something is wrong and you know to look for it. We explain the rules, the five account types and the trial balance in full in our dedicated guide to double entry bookkeeping.

A Worked Example of a Double Entry

Say your business sells £1,200 of consultancy work and the client pays straight into the bank. In double-entry bookkeeping that one event creates two entries:

Account	Debit	Credit
Bank account (asset increases)	£1,200
Sales income (income increases)		£1,200

The bank account is debited because the business now holds more money. Sales income is credited because the business has earned more revenue. Debits equal credits, so the books balance.

Now say you buy a £500 laptop on the business debit card:

Account	Debit	Credit
Computer equipment (asset increases)	£500
Bank account (asset decreases)		£500

Again, both sides total the same. Repeat this for every transaction and the system always knows what you own, what you owe, what you have earned and what you have spent, all from the same set of entries.

You rarely have to think about debits and credits yourself any more. Software such as Xero does the double entry behind the scenes when you create an invoice or match a bank transaction. But the method is why the software can produce a balance sheet at the press of a button, and it is why almost every business beyond the smallest sole trader uses double-entry.

One related decision is when transactions are recorded. Cash basis records income and expenses when money actually moves, and it is now the default for most sole traders' Self Assessment. Accrual basis records income when it is earned and costs when they are incurred, which limited companies must use for their statutory accounts. Our guide to accruals and prepayments explains the difference with examples.

Bookkeeper vs Accountant: What's the Difference?

People use the two terms interchangeably, but they cover different stages of the same process.

A bookkeeper records. Their job is the accurate, timely capture of transactions: the day-to-day work described above. Many bookkeepers hold qualifications from the Institute of Certified Bookkeepers (ICB) or the Association of Accounting Technicians (AAT), though the title itself is not protected, so anyone can call themselves a bookkeeper. That is worth remembering when you hire one.

An accountant interprets and reports. Accountants take the bookkeeping data and turn it into statutory accounts, corporation tax computations, Self Assessment returns and advice. Chartered and certified accountants (ACA, ACCA, CIMA) train for several years, and the work carries professional responsibility: an accountant signs off accounts, plans tax and represents you in dealings with HMRC.

A rough analogy: the bookkeeper builds the wall brick by brick, the accountant checks the structure and signs the building off. The two roles overlap in the middle (a good bookkeeper will prepare VAT returns, an accountant may tidy up bookkeeping at year-end), but the centre of gravity is different.

When do you need each? Almost every business needs bookkeeping from day one, whether you do it yourself or pay someone. You typically need an accountant when you have a limited company (statutory accounts and corporation tax are hard to get right alone), when your tax affairs go beyond a simple Self Assessment, or when you want advice rather than just records. Many firms, including IAK, offer both bookkeeping and accounting together, which avoids the classic problem of an accountant having to redo a year of messy books before they can even start.

What Records Does HMRC Require You to Keep?

Bookkeeping is not optional. UK law sets out what you must keep and for how long, and the rules differ by business type.

Limited companies must keep accounting records that show and explain the company's transactions, including all money received and spent, assets owned, debts owed and owing, stock at year-end, and the supporting documents: invoices, receipts, contracts and bank statements. These records must normally be kept for six years from the end of the financial year they relate to, and longer in some cases (for example, if a transaction covers more than one accounting period or HMRC has opened an enquiry). Failing to keep adequate records can lead to a fine of up to £3,000 from HMRC and, in serious cases, director disqualification.

Sole traders and partnerships filing Self Assessment must keep records of all sales and income, all business expenses, and any personal income, for at least five years after the 31 January submission deadline of the relevant tax year. So records behind your 2024 to 2025 return, due by 31 January 2026, must be kept until at least 31 January 2031.

VAT-registered businesses must additionally keep VAT records for at least six years: copies of all invoices issued and received, a VAT account summarising the VAT charged and reclaimed, and records of anything you cannot reclaim VAT on. Under Making Tax Digital, most of these records must now be kept digitally in compatible software.

Employers must keep PAYE records, including pay, deductions and reports to HMRC, for three years from the end of the tax year they relate to.

Two practical points. First, "records" includes the evidence, not just the totals: HMRC can ask to see the receipt behind an expense claim, and no receipt usually means no deduction. Second, digital copies are fine for most records, so a photographed receipt stored in your accounting software satisfies the requirement and is far harder to lose than a paper one.

Making Tax Digital and Modern Bookkeeping

Bookkeeping in the UK is now digital by law for a growing share of businesses, under HMRC's Making Tax Digital (MTD) programme.

MTD for VAT has applied to all VAT-registered businesses since April 2022. You must keep digital records and file VAT returns through MTD-compatible software. Typing figures from a paper cash book into HMRC's website is no longer an option.

MTD for Income Tax went live in April 2026 for sole traders and landlords with qualifying income over £50,000. If that is you, you now need to keep digital records and send quarterly updates to HMRC through compatible software, with a final declaration after the year-end. The threshold drops to £30,000 from April 2027 and is set to drop again to £20,000 from April 2028, pulling most self-employed people and landlords into the regime over the next few years.

The practical effect is that the shoebox of receipts and the once-a-year spreadsheet are finished as a bookkeeping system. Quarterly updates mean your records have to be broadly right every three months, not patched together each January.

The upside is that modern cloud software makes good bookkeeping far less work than it used to be. Bank feeds import transactions automatically, receipt-capture apps file the paperwork, invoices chase themselves, and you can see your real-time position from a phone. We work with Xero and can set up, migrate and train you on it, so MTD compliance becomes a by-product of records you would want anyway.

How Much Does Bookkeeping Cost in the UK?

Honest ranges, because costs vary with transaction volume and complexity:

Doing it yourself with software typically costs £15 to £40 per month for a Xero, QuickBooks or FreeAgent subscription. Your real cost is your time: budget a few hours a month for a simple business, more once you are VAT registered. Some banks bundle FreeAgent free with a business account.
A freelance bookkeeper usually charges £25 to £40 per hour in most of the UK, with London at the upper end. A small business might need 2 to 8 hours a month, so roughly £60 to £300 per month depending on volume.
Fixed monthly packages from a bookkeeping practice or accountancy firm typically run from around £50 to £100 per month for a low-volume sole trader up to £150 to £400 or more per month for a VAT-registered limited company with payroll. The fee usually includes software, reconciliations and VAT returns, and you know the cost in advance.

When you compare prices, compare scope. A cheap quote that excludes VAT returns, payroll postings or reconciliation is not cheap once those are added back. And bear in mind the hidden cost of bad bookkeeping: an accountant charging year-end rates to untangle twelve months of mess will usually cost more than having the books kept properly in the first place, before you count missed expense claims and VAT errors.

Common Bookkeeping Mistakes Small Businesses Make

We see the same avoidable errors again and again.

Mixing personal and business money. One bank account for both makes every reconciliation a guessing game and weakens the legal separation between you and a limited company. Open a separate business account on day one.
The shoebox of receipts. Receipts collected in a drawer and handed over once a year fade, go missing and arrive without context. Photograph receipts into your software the week you get them.
Never reconciling. If you do not regularly match the books to the bank, duplicated entries, missed income and bank errors go unnoticed. Unreconciled books are unverified books.
VAT errors. Claiming VAT without a valid VAT invoice, applying the wrong rate, missing the registration threshold (£90,000 of taxable turnover in any rolling 12 months), or mishandling reverse-charge items in construction. VAT mistakes attract penalties as well as the tax.
Misclassifying transactions. A capital purchase posted as a day-to-day expense, a loan repayment posted as a cost, or drawings posted as wages all distort your accounts and your tax.
Falling behind. Books done once a year, in a panic, are books full of mistakes. Little and often is the entire secret of painless bookkeeping.

Bookkeeping FAQs

Can I do my own bookkeeping?

Yes, and many sole traders do, especially below the VAT threshold. With cloud software and bank feeds, a simple business can be kept tidy in a few hours a month. The honest test is whether you actually do it. If the books are three months behind and you dread opening the software, paying someone £60 to £150 a month usually buys back more value than it costs.

Is bookkeeping hard?

The concepts are not hard, and software handles the double entry for you. What catches people out is the edge cases: VAT treatment, capital items, payroll postings and loan accounting. The discipline is harder than the theory. Doing it weekly is easy, reconstructing a year from bank statements is miserable.

What software should I use?

For most UK small businesses the realistic shortlist is Xero, QuickBooks Online and FreeAgent. All three are MTD-compatible, run bank feeds and handle VAT. We recommend and support Xero because its bank reconciliation and app ecosystem suit the small businesses we work with, but any of the three beats a spreadsheet. Pick one, connect your bank, and stick with it.

How often should bookkeeping be done?

Weekly is ideal, monthly is the minimum for a VAT-registered business. Quarterly MTD reporting effectively forces a monthly rhythm anyway, because you cannot fix three months of records in the week a return is due.

How IAK Can Help

Whether you want your books taken off your hands entirely or just set up properly so you can run them yourself, we can help. IAK Accountants provides fixed-fee bookkeeping for businesses across North London, with regular reconciliations, VAT returns and records that are always MTD-ready. We also handle Xero setup, migration and training, and our accounting services take the same clean records through to year-end accounts and tax.

If your bookkeeping is behind, messy or simply taking up evenings you would rather spend elsewhere, contact us for a free consultation.

What Is Bookkeeping and What Does a Bookkeeper Do?

John Kyprianou